The Manitoba time-of-flight mass spectrometer has been used to produce informative mass spectra from a variety of intractable biomolecules, including two neuropeptides and a number of protected nucleotides of masses oup to approximately 2100. It appears that the mass spectra contain sufficient information to completely determine the primary structure of such molecules. It is proposed to supplement the measurements on our time-of-flight instrument with higher resolution measurements on the Manitoba magnetic mass spectrometer. The long term objective of this work is to identify and characterize large biomolecules by mass spectrometry. Two classes of compounds will be studied initially: 1) Neuropeptides - More of the available synthetic peptides will be examined first. Later a search will be carried out for new physiologically important neuropeptides, using purified material isolated from secretory granules at nerve terminals, (in the Manitoba Pharmacology Dept.). 2) Fully Protected Oligonucleotides - First it is intended to investigate the spectra of more short chains of nucleotides with various permutations of bases and protecting groups. This is expected to establihs the principle for sequence determination. In the longer term, it is hoped to use these principles to determine the sequence and purity of small quantities (less than or equal to 1Mug), of longer oligonucleotide chains, perhaps up to 20 nucleotides in lenght, (to be prepared at McGill).